Users, for example caregivers of infants, rely on disposable absorbent articles to make their lives easier. Disposable absorbent articles, such as adult incontinence articles and diapers, are generally manufactured by combining several components. These components typically include a liquid-permeable topsheet; a liquid-impermeable backsheet attached to the topsheet; and an absorbent core located between the topsheet and the backsheet. When the disposable article is worn, the liquid-permeable topsheet is positioned next to the body of the wearer. The topsheet allows passage of bodily fluids into the absorbent core. The liquid-impermeable backsheet helps prevent leakage of fluids held in the absorbent core. The absorbent core generally is designed to have desirable physical properties, e.g. a high absorbent capacity and high absorption rate, so that bodily fluids can be transported from the skin of the wearer into the disposable absorbent article.
Frequently one or more components of a disposable absorbent article are adhesively bonded together. For example, adhesives have been used to bond individual layers of the absorbent article, such as the topsheet and backsheet together. Adhesives have also been used to bond discrete components, such as fasteners and leg elastics or cuffs, to the article. The adhesive is often called a construction adhesive because it is used to help construct the absorbent article from individual components.
In many instances, a hot-melt adhesive, i.e. a polymeric formulation that is heated to substantially liquefy the formulation prior to application to one or both materials when making a laminate, is used as a construction adhesive. While such formulations generally work, they can be costly and their performance properties can be improved. For example:                It is desirable that the adhesive remain in its intended location after the absorbent article has been assembled and not flow when “cold” (i.e. at normal ambient conditions of less than about 40° C.). Such “cold flow” has been found to result in undesirable adhesion between surfaces of the absorbent article that are not intended to adhere to each other (e.g. a portion of the topsheet in a diaper that has been folded for packaging may adhere to another facing portion of the topsheet).        Such adhesives also have a desirable “open time” (i.e. the time when the hot melt adhesive is at a high enough temperature that it can join one material to another. If open time is too short, the adhesive is not suitable as a construction adhesive because components cannot be reliably assembled. If open time is too long the adhesive may transfer from the assembled components of the absorbent article to components of the production line with resulting hygiene issues.Thus, there is a continuing need for improved construction adhesives for use in absorbent articles and the production thereof.        